An optic system such as a camera comprises a lens and an image receiver. The focal length of the lens, together with the distance between the lens and image receiver, determine the distance that a user must position the lens from an object in order to obtain a focused reproduction of the object at the image receiver.
In some optics systems, the distance between the lens and image receiver is fixed. In other optics systems, the distance between the lens and image receiver may be varied, thereby providing the optic system with a variable focusing system.